Entry and exit stacking system

ABSTRACT

Large sheets are separated from a first stack by a series of sequentially actuated vacuum cups, transferred to a conveyor arrangement, and ultimately delivered to a stacking arrangement which includes a series of rollers supported at their ends by endless chains for movement above a second stack. Movement of the chain-supported rollers in the direction opposite to sheet delivery thereto results in the sheet which had been supported on the rollers being gradually deposited onto the second stack.

United States Patent [191 Jarman Oct. 14, 1975 ENTRY AND EXIT STACKING SYSTEM [22] Filed: Oct. 23, 1973 [21] Appl. No.: 408,457

[52] US. Cl 271/5; 214/6 DK; 271/91; 271/190 [51] Int. Cl. B65H 29/36; B65H 3/08 [58] Field of Search 271/3-5, 46, 271/182, 190, 91; 214/6 DK [56] References Cited UNITED STATES PATENTS 1,442,718 1/1923 Free 271/90 2,859,965 11/1958 Pabst et a1. 271/190 2,936,171 5/1960 Williams 271/91 X 3,020,043 2/1962 Winkler et al.. 271/5 3,273,726 9/1966 Buccione 271/46 X 3,411,638 11/1968 Dryon 214/6 DK 3,615,129 10/1971 Drawe et a1. 1. 271/3 X 3,698,572 10/1972 Dahlem et a1 214/6 DK 3,768,807 lO/l973 Spengler 271/5 X FOREIGN PATENTS OR APPLICATIONS 250,529 7/1926 United Kingdom 271/46 Primary Exanz'inerRichard A. Schacher Assistant ExaminerBruce l-l. Stoner, Jr. Attorney, Agent, or FirmAlter and Weiss ABSTRACT ited onto the second stack.

8 Claims, 8 Drawing Figures US. Patent Oct. 14, 1975 SheetlofZ 3,912,253

WASHER WASHER /3 Q Q C t WASHER WASHER O M'd FIG 7 WOC ENTRY AND EXIT- STACKING SYSTEM This invention is concerned with material handling equipment, and more particularly, to entry and exit stacking equipment. Large sheet material is awkward to handle; especially when the material is of thin gauge. The large sheet material, besides being clumsy, is heavy and hard to hold while at the same time it is extremely vulnerable to being creased or permanently bent.

Handling equipment for such material has been provided in the past that included vacuum cups and/or magnetic retainers for retaining and supporting the sheet material as it passes from the conveyor to the stacking retainer. A problem involved with this type of equipment is that the equipment itself often mars the finish of the sheet material. Thus, instead of having permanently bent or nicked material, a marred sheet of material results. This problem is especially injurious if the handling equipment is removing the material at a station where the material is being washed. Thus, prior to the final washing process it is possible to handle the sheet material with magnets where the sheet material is magnetic metal or with vacuum cups. While this does leave marks on the material the washing process removes these marks. Thus, the major difficulty in handling the sheet material occurs after the final washing process when the sheet material must be in excellent aesthetic condition.

Accordingly, an object of this invention is to provide a new and unique entry and exit stacking system.

A related object of the invention is to provide an entry stacking system equipped with apparatus for transferring sheet material from an entry stack onto an entry conveyor for final transportation to a processing station.

Another object of the invention is to provide apparatus for transferring sheet material including nonmagnetic sheet material from a stacking hydraulic lift table to a conveyor wherein vacuum cup hoisting cylinders are used to grip the top sheet of the sheet material and wherein the vacuum cylinders are sequentially energized to eliminate the vacuum otherwise created between the sheets of material. Thus, the sheets are not lifted straight up, but are lifted on a bias and are nonetheless adequately supported.

Yet another object of the invention is to provide vacuum equipment of the above mentioned type wherein the vacuum cups are equipped with blow-offs for quickly releasing the sheets onto the entry conveyor.

Yet another object of the invention is to provide power rolls for conveying stacks onto the feeder table.

Yet another object of the invention is to provide means for transferring the sheet material from the exit conveyor coming from the processing station to a final stack on a stacking table. The apparatus handles the material so as to neither mar nor blemish the sheet material.

Yet another object of the present invention is to provide apparatus for transferring individual sheets of sheet material from an exit conveyor to a stacking table that maintains approximately a height equal to the exit conveyor.

Yet another object of the invention is to provide a chain driven roller type stacker for receiving the sheet material from the exit conveyor. The stacker longitudinally sets the sheet material on the stack; removing its support a little at a time so as to prevent blemishing or marring the sheet material.

Yet another object of the invention is to provide transfer apparatus including a chain driven roller type stacker wherein the chain has rubber covered rollers attached thereto which rollers rotate on their axes as well as move with the chain around drive wheels at either end of the transfer apparatus to drop the sheets onto the stack as the rollers move away from the stack.

In accordance with one preferred embodiment of the present invention, the entry and exit stocking system comprises a processing station fed by an entry conveyor and serviced by an exit conveyor. The system is capable of handling sheet material of all kinds, but especially light gauge material wherein the peculiar problems of handling large sheet material are compounded.

The entry conveyor is fed by an entry stack transfer system wherein power rolls are provided for conveying stacks of sheet material into a sheet material feeder. The feeder includes timed vacuum cup apparatus whereby each individual sheet is lifted at an angle to prevent the vacuum otherwise created between the sheets of material. The vacuum between the sheets causes more than one sheet to be lifted at a time and the bottom sheet usually falls and is damaged.

The entry conveyor transfers the sheet material into a processing station such as a washer and an exit conveyor is provided for removing the sheet material from the processing station. The exit conveyor leads to rubber covered pinch rollers which grasp the individual sheets as they come off the exit conveyor and feeds them to the exit stacking apparatus. The exit stacking apparatus includes a chain driven roller type stacker wherein there are a pair of parallel spaced apart endless chains. A set of rollers reaches across the chains transverse to the direction of movement of the chains, and moves with the chains. The set of rollers is arranged so that there is a large space between the last roller and the first roller, and preferrably, only one level of the chains are provided with rollers. The length of the chain. is longer'than the length of the sheet material being handled.

Transfer rollers between the pinch rollers and the chain rollers support the sheets as they are set on the chain rollers while the chain rollers are all at the lower level. The chain rollers are bearing mounted for independent rotational movement. The pinch rollers force the sheets onto the chain rollers until the sheet extends its entire length on the chain rollers and is supported thereby, above the stacking table. The chains have a drive sprocket at opposite ends thereof and are actuated to move the rollers.

The chain can move so that the bottom layer moves toward or away from the pinch rollers. In a preferred embodiment they move toward the pinch rollers.

Simultaneously with the movement of the sprockets a brake type arrangement is actuated to press down on the sheet material over a broad surface and thereby keep the sheet material from moving with the movement of the chain so that it stays in its place above the stack. As the roller furthest from the pinch rollers is moved toward the pinch rollers, the end of the sheet farthest from the pinch rollers drops the slight distance downward to the point of stacking. The sheet material is supported by the diminishing number of rollers in the lower level as it is laid lengthwise on top of the stack. The rollers move up to the top level and back around,

making the complete circuit, until they are in their original position aligned to receive the next sheet of sheet material.

Thus, the sheet material is stacked gently without dirtying, blemishing or marring the sheet material, in any way.

The above mentioned and other objects and features ofthis invention together with the manner of obtaining them will become more apparent and the invention itself will be best understood by making reference to the following description of a preferred embodiment of the invention taken in conjunction with the accompanying drawings; in which:

FIG. 1 is a pictorial view of the exit station including the unique apparatus for stacking the sheet material as it is removed from the exit conveyor;

FIG. 2 is a side view of the complete entry and exit system;

FIG. 3 is a plan view of the complete system;

FIG. 4 is a detailed side view of the stacker mechanism shown pictorially; and

FIGS. 5 8 are schematic stop motion views showing in different positions of the stacker mechanism during the stacking operation.

It should be understood that in the drawings a bare minimum of accessory equipment is shown. Thus, for example, in FIG. 3 the plan view does not completely show the feeding equipment. For example, the framework of the feeder equipment is not shown. Similarly, the framework of the stacking mechanism is omitted in FIG. 1.

As shown in FIG. 1 the stacking mechanism or station 11 comprises a pair of parallel spaced apart chain drive assemblies 12 and 13. Each of the chain drive assemblies includes a sprocket wheel, such as sprocket wheel 14, used to drive the chain, such as shown at 16. The chains hold a series of ball bearing mounted rubber covered rollers, such as roller 17. There are sufficient rollers to extend along the bottom of the endless chains to completely support a sheet of the sheet material thereon.

Also included in the stacking mechanism is means for retaining the sheet material such as sheet 36 in position over the stack 18 even when the chain is being moved around the sprockets. When the chain is so actuated, the rollers move with the chain and eventually all of the rollers are on the upper tier of the endless chains. Thus, in the normal position, the rollers are located at the lower tier, of the endless chain.

The lower tier 19 with the rollers attached moves around the sprocket wheels so that the rollers go along until they are positioned at the top tier 20.

Brake means retains the sheet material in place so that it does not move with the chain assembly but is dropped onto the stack 18. The brake means is shown as an angle iron 21. It should be realized that other configurations, such as channel irons could be used. A key characteristic of the brake means is that it presents a flat surface to the sheet material. The angle iron 21 is shown as having a bottom surface covered with rubber 22. The angle iron is attached to a piston 23 of the hydraulic cylinder 24 which is mounted on a frame 26. The frame extends between the upper and lower tier of the chains so as not to interfere with the movement of the chains. When the cylinder is energized, then the piston 23 extends and forces the rubber covered brake means 21 against the sheet, keeping the sheets from moving as the rollers are moved with the chain to the top tier.

The stack 18 is shown as supported by a hydraulic lift type table shown schematically as 27. These type of tables are commercially available. The table is such that every time a new sheet of material is placed on it, it automatically lowers to maintain the top of the stck at approximately the same distance above the ground. The table 27 includes a top horizontal table top 28 supported by biased scissor supports 29 and 31. Not shown, is a simple knee action lift mechanism that is hinged at the top and the bottom of the frame and which is operated by a hydraulic ramp.

Also shown in FIG. 1 are the pinch rollers 33 and 34 which receive the sheet material, such as sheet 36 as it comes from the exit conveyor. The pinch rollers are preferrably actuated by hydraulic motor, not shown, and are covered with rubber, or any other protective type coating, to assure that the plate 36 is not marred as it is forced through the pair of pinch rollers 33 and 34 and onto the series of rollers 15.

The entire system is shown in FIG. 2. The system includes a feeder station 37, a processing station 38, where the sheet material is operated on in some manner, such as, for example, where it is automatically washed and the final stacking station shown in FIG. 1 as 11. The plan view of the entire system is shown in FIG. 3.

The feeder station includes means for handling complete stacks of sheet material that are going to be processed in the processing station 38. The interface between the feeder station 37 and the processing station 38 is the entry conveyor 39 which is any type of regularly used conveyor apparatus. Coupling the processing station 38 with the stacking station 11 is an exit conveyor 41. The exit conveyor also can be any type of conveyor that is commonly used for transporting sheet material.

The stacks of sheet material are brought to the station 37 either over other conveyors, by lift trucks or in any other manner. The stacks are placed upon power rolls, such as shown at 42, positioned to transfer the stacks to the hydraulic lift table 43 at the station 37. When the stack that was on the table 43 has been completely transferred onto the entry conveyor 39, then the hydraulic lift table 43 it is vertically positioned in the normal manner until it is on a level with the power roll. At that time the power rolls are energized and the stack is transferred to the hyraulic lift table 43. The hydraulic lift table is then raised so that the top sheet is level with entry conveyor 39.

Means are provided for transferring a single sheet at a time to the entry conveyor. These means can be magnetic, or they can be vacuum, such as shown in the drawings. The vacuum feeder is shown more or less schematically at 44. It comprises a transversing carriage 46 mounted on rails 47, through rail wheels, such as wheel 48. The carriage transports a series of vacuum cup hoisting cylinders, such as vacuum cup hoisting cylinders 49, 51, 52 and 53 (FIG. 2). Actually, as shown in FIG. 3, there are pairs of cylinders operating vacuum cups 54, 56, 57, 58, 59, 61, 62 and 63.

Means are provided to prevent a vacuum from being created between the top sheet of material that is being lifted and the sheet directly underneath that top sheet. Often times as the top sheet is lifted straight up there is a tendency for the sheet immediately below it to also be lifted up because of the vacuum formed between the top sheet and the next adjacent sheet.

Programming means 64 shown connected to each of the cylinders is a timing arrangement which causes the first cylinders to operate vacuum cups 54 and 56 first. Subsequently, the next cylinders are energized to operate the vacuum cups 57 and 58. Thus, the conveyor end of the sheet is lifted first followed shortly thereafter by the next portion of the sheet.

When the cups have all been vacuumized so that the sheet is lifted, then the carriage 46 is moved by a cable and motor arrangement schematically shown as cable 66 and motor 67 moving the cart backwards and forwards over rail 47. Of course, the cart can be moved in many different manners. The rail wheels, such as rail wheel 48, may themselves be energized for rotation upon receipt of the proper signal.

When the cart is directly above the entry conveyor 39, then the vacuum is released from the cups to release the transported sheet. The vacuum cups are equipped with blow-offs so that a quick release can be accomplished. The entry conveyor 39 comprises powered rollers or powered chains. The rollers are preferrably rubber coated to protect the material being transported. The chains shown at 68 are operated by a pinion schematically shown at 69 which in turn is coupled to some type of electrical or hydraulic drive motor.

The sheet material is thus brought into a processing station 38 where it is operated upon in some manner, for example, in this case it is washed. As it comes out of the processing station 38 it travels on exit conveyor 41 which also comprises an endless chain 71 motivated by an operated pinion wheel 72. 1

Means are provided for transporting the sheet material on the exit conveyor 41 to the stacking station. These means include entry rolls 73 located between the conveyor and the pinch rolls 33 and 34 previously discussed. All of these rolls are preferrably rubber-covered to protect the material being transported. The pinch rolls and the exit conveyor are powered so that the sheet material is forced from the conveyor to the pinch rolls where the pinch rolls then in turn force the material onto the chain driven roller type stacker 76. The stacker is shown in greater detail in FIG. 4. More particularly, therein again is seen the stack 18 mounted on the table top 28. Immediately above the stack are shown the rollers of the chain driven roller, such as rollers 77, 78, 79 and 81, for example, which are rotatably coupled to the chain at the chain portion 19. In the normal position the rollers are in the lower tier immediately above the stack.

The sheet material such as sheet 36 is pushed on top of the chain driven rollers by the pinch rollers as shown in the stop action drawings FIGS. 5 7. The brake apparatus 20 is normally raised so that it avoids juxtaposition to the sheet material.

FIG. 5 shows the sheet material as it leaves the processing station 38 and is on exit conveyor 41. FIG. 6 shows the pinch rollers 33 and 34 forcing the sheet material 36 on top of the rollers that are in the lower tier located above the stack 18.

FIG. 7 shows the sheet material 36 completely within the chain driven roller type stacker and also shows the brake means actuated to be juxtaposed to the sheet 36.

The pinion wheels, such as pinion wheels 14a, 14b are actuated to rotate in the counter-clockwise direction so that the chain section 19 moves around pinion wheel 14a along with rollers 15 until as shown in FIG. 8 some of the rollers, such as roller 25, are above the pinion wheels whereas some of the rollers, such as roller 17, for example, are still below the driven pinion wheel 14a. As the rollers are removed from supporting the sheet which is prevented from moving by the brake assembly 20, the end of the sheet 36 is gently laid on top of the stack. The rollers are then brought back around to the original position shown in FIG. 5 at which time the chain is again stopped in the position to receive the next sheet of material.

When the required number of sheets are supplied to the stack then the table 27 is lowered until it is on a level with the ste of rollers shown at 91 in FIG. 3. The lift table is equipped with power rolls also shown in FIG. 3 at 92. These rolls are then actuated so that the stack is moved to the rolls 91, ready to be transferred from that point while another stack can be assembled onto the table.

Thus, in operation the sheets are originally brought to the entry conveyor by the vacuum equipment wherein the vacuum cups are sequentially actuated to avoid lifting more than one sheet at a time. The entry conveyor delivers a sheet to the processing station 38. From the processing station 38 the sheet is brought to the exit conveyor. The exit conveyor delivers it over to the entry rolls which are preferrably rubber covered. Going from the entry rolls the pincher rolls pickup the sheets and deliver them to the chain driven roller type stacker to gently place the fragile sheet materiual on top of the stack.

While the principals of the invention have been described in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example, and not as a limitation on the scope of the invention.

I claim:

1. A stacking system for use in handling sheet material said stacking system comprising main conveyor means for moving said sheet material;

said main conveyor means having an input side where sheet material is fed onto said main conveyor means and an output side where said sheet material is dispensed from said main conveyor means;

said main conveyor means moving said sheet material in a first direction going from said input side to said output side,

stacking means for stacking said sheet material received from the output side of said main conveyor means;

said stacking means comprising support means for setting individual sheets of said sheet material on a stack by sequentially laying portions of the individual sheets onto the stack, while supporting the rest of the sheet;

said support means comprising stacking conveyor means including endless chain means;

said endless chain means comprising a pair of spaced apart chains, each having a bottom level and a top level;

rollers sequentially attached across the bottom level of said pair of chains;

means for moving said chains so that the rollers are moved to the top level;

means for transferring said sheet material from said main conveyor to said support means, while said rollers are at the bottom level so that the entire sheet material is supported by the rollers on the bottom level;

means for thereafter moving said chains;

means for retaining said sheet material in place while said chain and rollers are moving;

ball bearing means on said rollers so that said rollers rotate around their own axes while moving away from the bottom of said sheet material;

said sheet material dropping onto the stack bit by bit as said rollers are removed from the bottom thereof; and

said support means moving in a second direction opposite to said first direction for sequentially removing portions of said support means from said sheet, while being retained on the remaining portions of said sheet material so that said sheet material is set on the stack bit by bit without the marring of said sheet material, while being stacked.

2. The stacking arrangement and system of claim 1 wherein said means for retaining said sheet in plac comprises brake means, and

means for causing said brake means to abut said sheet.

3. The stacking system of claim 2 wherein said means for causing said brake means to abut said sheet material comprises hydraulic cylinder and piston means attached to said brake means,

said brake means abutting said sheet when said piston is extended from said cylinder.

4. The stacking system of claim 3 wherein said brake means comprises angle iron means,

said angle iron means having a rubber lining on the bottom thereof, and

said rubber lining being positioned to abut said sheet material when it is desired to retain said sheet material in place as the chain and rollers are moved.

5. An entry and exit stacking system for use in conveying large sheet material to a processing station from a first stack through a processing station to a second stack,

said system comprising entry conveyor means leading 1 into said processing station,

exit conveyor means for removing the sheet material fromthe processing station by moving the sheet material in a first direction,

exit stacking means for automatically stacking the material removed from the processing station by the exit conveyor means,

means for transferring the sheet material from the first stack to the entry conveyor means;

said last named means including vacuum equipment for lifting the individual sheet material from the stack and transporting said individual sheets to the entry conveyor,

said vacuum equipment comprising a series of vacuum cup hoisting cylinders longitudinally arranged above said first stack,

said vacuum cup hoisting cylinders being energized sequentially so that said sheet material is slantedly lifted from the stack to prevent a vacuum from forming between the sheet material being lifted and the next sheet on the stack,

said exit stacking means comprising endless chain means for setting the individual sheets on the exit stack,

said endless chain means comprising a pair of spaced apart chains, each having a bottom level and a top level,

rollers sequentially attached across the bottom level of said pair of chains,

means for moving said chains in a direction opposite to said first direction so that the rollers are moved to the top level,

means for transferring said sheet material to said exit stacking means in said first direction while said rollers are at the bottom level so that the entire sheet material is supported by the rollers on the bottom level,

means for thereafter moving said chains,

means for retaining said sheet material in place while said chains and rollers are moving, and

said sheet material dropping onto the stack bit by bit as the rollers are removed from the bottom thereof.

6. The entry and exit stacking system of claim 5 wherein said means for retaining said sheet in place comprises brake means, and

means for causing said brake means to abut said sheet.

7. The entry and exit stacking system of claim 6 wherein said means for causing said brake means to abut said sheet comprises hydraulic cylinder and piston means attached to said brake means, and

said brake means abutting said sheet when said piston is extended from said cylinder.

8. The entry and exit stacking system of claim 7 wherein said brake means comprises angle iron means,

said angle iron means having a rubber lining on the bottom thereof, and

said rubber lining being positioned to abut said sheet material when it is desired to retain said sheet material in place as the chain and rollers are moved. 

1. A stacking system for use in handling sheet material said stacking system comprising: main conveyor means for moving said sheet material; said main conveyor means having an input side where sheet material is fed onto said main conveyor means and an output side where said sheet material is dispensed from said main conveyor means; said main conveyor means moving said sheet material in a first direction going from said input side to said output side, stacking means for stacking said sheet material received from the output side of said main conveyor means; said stacking means comprising support means for setting individual sheets of said sheet material on a stack by sequentially laying portions of the individual sheets onto the stack, while supporting the rest of the sheet; said support means comprising stacking conveyor means including endless chain means; said endless chain means comprising a pair of spaced apart chains, each having a bottom level and a top level; rollers sequentially attached across the bottom level of said pair of chains; means for moving said chains so that the rollers are moved to the top level; means for transferring said sheet material from said main conveyor to said support means, while said rollers are at the bottom level so that the entire sheet material is supported by the rollers on the bottom level; means for thereafter moving said chains; means for retaining said sheet material in place while said chain and rollers are moving; ball bearing means on said rollers so that said rollers rotate around their own axes while moving away from the bottom of said sheet material; said sheet material dropping onto the stack bit by bit as said rollers are removed from the bottom thereof; and said support means moving in a second direction opposite to said first direction for sequentially removing portions of said support means from said sheet, while being retained on the remaining portions of said sheet material so that said sheet material is set on the stack bit by bit without the marring of said sheet material, while being stacked.
 2. The stacking arrangement and system of claim 1 wherein said means for retaining said sheet in place comprises brake means, and means for causing said brake means to abut said sheet.
 3. The stacking system of claim 2 wherein said means for causing said brake means to abut said sheet material comprises hydraulic cylinder and piston means attached to said brake means, said brake means abutting said sheet when said piston is extended from said cylinder.
 4. The stacking system of claim 3 wherein said brake means comprises angle iron means, said angle iron means having a rubber lining on the bottom thereof, and said rubber lining being positioned to abut said sheet material when it is desired to retain said sheet material in place as the chain and rollers are moved.
 5. An entry and exit stacking system for use in conveying large sheet material to a processing station from a first stack through a processing station to a second stack, said system comprising entry conveyor means leading into said processing station, exit conveyor means for removing the sheet material from the processing station by moving the sheet material in a first direction, exit stacking means for automatically stacking the material removed from the processing station by the exit conveyor means, means for transferring the sheet material from the first stack to the entry conveyor means; said last named means including vacuum equipment for lifting the individual sheet material from the stack and transporting said individual sheets to the entry coNveyor, said vacuum equipment comprising a series of vacuum cup hoisting cylinders longitudinally arranged above said first stack, said vacuum cup hoisting cylinders being energized sequentially so that said sheet material is slantedly lifted from the stack to prevent a vacuum from forming between the sheet material being lifted and the next sheet on the stack, said exit stacking means comprising endless chain means for setting the individual sheets on the exit stack, said endless chain means comprising a pair of spaced apart chains, each having a bottom level and a top level, rollers sequentially attached across the bottom level of said pair of chains, means for moving said chains in a direction opposite to said first direction so that the rollers are moved to the top level, means for transferring said sheet material to said exit stacking means in said first direction while said rollers are at the bottom level so that the entire sheet material is supported by the rollers on the bottom level, means for thereafter moving said chains, means for retaining said sheet material in place while said chains and rollers are moving, and said sheet material dropping onto the stack bit by bit as the rollers are removed from the bottom thereof.
 6. The entry and exit stacking system of claim 5 wherein said means for retaining said sheet in place comprises brake means, and means for causing said brake means to abut said sheet.
 7. The entry and exit stacking system of claim 6 wherein said means for causing said brake means to abut said sheet comprises hydraulic cylinder and piston means attached to said brake means, and said brake means abutting said sheet when said piston is extended from said cylinder.
 8. The entry and exit stacking system of claim 7 wherein said brake means comprises angle iron means, said angle iron means having a rubber lining on the bottom thereof, and said rubber lining being positioned to abut said sheet material when it is desired to retain said sheet material in place as the chain and rollers are moved. 